Generally, a touch panel has both a displaying function and a touch control function. The touch control function may be implemented according to a resistive sensing technology, a capacitive sensing technology or an infrared sensing technology etc.
FIG. 1 is a schematic side view illustrating a conventional touch panel. As shown in FIG. 1, from bottom to top, the touch panel 1 includes a lower polarizer 18, a thin film transistor (hereinafter, TFT) substrate 19, a liquid crystal layer 17, a color film substrate 15, an upper polarizer 13, and a protective glass layer 11. Moreover, plural transparent electrodes 12 are formed in the upper polarizer 13 in order to provide a touch control function.
For achieving the displaying function, the transparent electrode 12 of the touch panel 1 has the transparent property and the electrically-conductive property. Generally, the transparent electrode 12 is made of a transparent conductive oxide (hereinafter, TCO) material.
For realizing the locations of the touch points, the plural transparent electrodes 12 are arranged in the upper polarizer 13. That is, every two adjacent transparent electrodes 12 are separated from each other by a gap. Although the transparent electrodes 12 are light-transmissive, the transmittance of the locations corresponding to the transparent electrodes 12 is lower than the transmittance of the other locations of the touch panel by about 7%. In other words, the arrangement of the transparent electrodes 12 may influence the transmittance of the touch panel.
As shown in FIG. 1, the light beam L1 is directly transmitted through the upper polarizer 13, and the light beam L2 is transmitted through the transparent electrodes 12. Since the transmittance of the locations corresponding to the transparent electrodes 12 is lower, the light beam L1 is visually brighter than the second light beam L2.
FIG. 2 schematically illustrates an image shown on the conventional touch panel. In case that an image is shown on the touch panel, the arrangement of the transparent electrodes 12 may result in non-uniform brightness distribution of the image. In other words, the conventional touch panel has a visibility issue. Therefore, there is a need of providing a transparent electrode layer with improved transmittance while maintaining the touch control function.